不采用#include <openssl/aes.h> 应该怎么写

如果不使用`<openssl/aes.h>`库，可以自己实现AES算法，下面给出一个基于AES的CMAC算法的C语言代码示例（不使用任何第三方库）：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define BLOCK_SIZE 16   //AES算法中数据块的长度为16字节

typedef struct {
    unsigned char k[16];
    unsigned char l[16];
    unsigned char r[16];
    unsigned char subkey1[16];
    unsigned char subkey2[16];
} cmac_ctx;

void aes_encrypt(unsigned char *in, unsigned char *out, unsigned char *key)
{
    //AES算法的实现
    //...
}

void cmac_init(unsigned char *key, cmac_ctx *ctx)
{
    //生成子密钥K1和K2
    unsigned char zero[BLOCK_SIZE] = {0};
    aes_encrypt(zero, ctx->subkey1, key);
    if ((ctx->subkey1[0] & 0x80) == 0) {
        for (size_t i = 0; i < BLOCK_SIZE; i++)
            ctx->subkey1[i] <<= 1;
    } else {
        for (size_t i = 0; i < BLOCK_SIZE; i++) {
            ctx->subkey1[i] = (ctx->subkey1[i] << 1) | (ctx->subkey1[i+1] >> 7);
        }
        ctx->subkey1[BLOCK_SIZE-1] ^= 0x87;
    }
    memcpy(ctx->subkey2, ctx->subkey1, BLOCK_SIZE);

    //处理L和R
    unsigned char zero2[BLOCK_SIZE] = {0};
    aes_encrypt(zero2, ctx->l, key);
    for (size_t i = 0; i < BLOCK_SIZE; i++) {
        if ((ctx->l[i] & 0x80) == 0) {
            ctx->l[i] <<= 1;
        } else {
            ctx->l[i] = (ctx->l[i] << 1) | (ctx->l[i+1] >> 7);
        }
    }
}

void cmac_update(unsigned char *msg, size_t msg_len, cmac_ctx *ctx)
{
    //处理L和R
    size_t n = (msg_len + BLOCK_SIZE - 1) / BLOCK_SIZE;
    for (size_t i = 0; i < n; i++) {
        size_t len = (i == n-1) ? msg_len % BLOCK_SIZE : BLOCK_SIZE;
        unsigned char tmp[BLOCK_SIZE];
        memcpy(tmp, &msg[i*BLOCK_SIZE], len);
        if (len < BLOCK_SIZE) {
            tmp[len] = 0x80;
            for (size_t j = len+1; j < BLOCK_SIZE; j++) {
                tmp[j] = 0x00;
            }
        }
        for (size_t j = 0; j < BLOCK_SIZE; j++) {
            ctx->r[j] ^= tmp[j];
        }
        aes_encrypt(ctx->r, ctx->r, ctx->k);
    }
}

void cmac_final(unsigned char *msg, size_t msg_len, unsigned char *mac, cmac_ctx *ctx)
{
    //处理最后一个数据块
    unsigned char tmp[BLOCK_SIZE];
    if (msg_len % BLOCK_SIZE == 0) {
        memcpy(tmp, &msg[msg_len-BLOCK_SIZE], BLOCK_SIZE);
        for (size_t i = 0; i < BLOCK_SIZE; i++) {
            tmp[i] ^= ctx->subkey1[i];
        }
    } else {
        size_t pad_len = BLOCK_SIZE - (msg_len % BLOCK_SIZE);
        memcpy(tmp, &msg[msg_len-(BLOCK_SIZE-pad_len)], BLOCK_SIZE-pad_len);
        tmp[BLOCK_SIZE-pad_len] = 0x80;
        for (size_t i = BLOCK_SIZE-pad_len+1; i < BLOCK_SIZE; i++) {
            tmp[i] = 0x00;
        }
        for (size_t i = 0; i < BLOCK_SIZE; i++) {
            tmp[i] ^= ctx->subkey2[i];
        }
    }
    for (size_t i = 0; i < BLOCK_SIZE; i++) {
        ctx->r[i] ^= tmp[i];
    }
    aes_encrypt(ctx->r, mac, ctx->k);
}

void cmac(unsigned char *key, unsigned char *msg, size_t msg_len, unsigned char *mac)
{
    cmac_ctx ctx;
    memset(&ctx, 0, sizeof(cmac_ctx));
    memcpy(ctx.k, key, BLOCK_SIZE);
    cmac_init(key, &ctx);
    cmac_update(msg, msg_len, &ctx);
    cmac_final(msg, msg_len, mac, &ctx);
}

int main()
{
    unsigned char key[] = "1234567890123456";
    unsigned char msg[] = "Hello, world!";
    unsigned char mac[BLOCK_SIZE];

    size_t msg_len = strlen(msg);
    cmac(key, msg, msg_len, mac);

    printf("Message: %s\n", msg);
    printf("MAC: ");
    for (int i = 0; i < BLOCK_SIZE; i++) {
        printf("%02x", mac[i]);
    }
    printf("\n");

    return 0;
}

需要注意的是，此示例仅用于演示用途，实际应用中需要根据具体情况进行修改和优化。